presynaptic

1.a presynaptic nerve fiber; a presynaptic stimulus.

触前的神纤维；触前的刺激

2.It seems reasonable to conclude that Toosendanin is a presynaptic blocking agent.

这些结果表明，川楝素是一个选择性地作用于触前的神肌肉传递阻遏剂。